Electric lamp



(No Model.)

L. DAFT.

ELECTRIC LAMP.

Patented Nov. 1,1881.

N. FUCHS. mmm-umugrnplmr. wnshmgmn. D. c.

l UNITED STATES kPATENT OFFICE.

LE() DAF'I, OF GREENVILLE, NEW JERSEY.

ELECTRIC LAMP.

SPECIFICATION formingpart of Letters Patent No. 249,019-, dated November 1, 1881.

Application filed December 20, 1880. (No model.) l

To all whom it may concern:

Be it known that I, LEO DAFT, a subject of of the Queen of Great Britain, residing at Greenville, in the county of Hudson, in the State of New Jersey, have invented new and useful Improvements in Electric Lamps', of which the following is a specification.

My invention relates to electric-light mechanism; and it consists in the following specific device, or its equivalent, whereby the carbon sticks usually employed are automatically adjusted and kept in such a position and relation to each other that a continuous and effective light shall be had without the necessity of manual interference.

My invention also relates to the arrangement and construction of the frame supporting the electric lamp, as will hereinafter appear, whereby a perfect insulation between the two carbons is effected and the light is improved.

The drawin g represents a sectional front view of my lamp.

In this drawing, the letter A designates a helix of insulated wire in the form of a tube or hollow cylinder, which rests upon the upper yoke or traverse, A', connected by glass tubes E E with the lower traverse, G.

Within the axial cavity of the helix A is contained the iron core C and the rod B, which latter is fixed or iir-mly secured to the core and moves together therewith freely within the y cavity of the helix, the rod being guided in the top plate of the helix and in a bridge, N, which is secured to the under side of the traverse A'. The rod B is by preference made in two sections, which are united by a screw-coupling, a, and in the lower tubular section, B', is placed loosely the upper or positive carbon, F, so that the carbon moves freely therein and can descend by its inherent gravity.

To the lower end of the tubular section B' of the rod B are secured carbon-detainin g fm gers b,which extend from an annular head,o, screwed or otherwise secured to the end of the section B'. These iin gers b are by preference made of platinum, porcelain, or other refractory material, to avoid injury thereto bythe heat to which they are exposed when the lamp is in operation, and' their points bear against the tapering sides of the lower end of the carbon F in such a manner that as the carbon is consumed the fingers allow it to sink down automatically and without requiring any manual interference until nearly all the carbon is consumed, while at the same time any upward motion ofthe rod B and core C is shared by the carbon.

0n the rod B is secured by a set-screw, el, a ring, e, which acts as a stop to the upward motion of the parts, as hereinafter more fully explained.

The traverse G is fully insulated from the traverse A by being connected thereto through the glass tubes E E, as before stated. From the traverse G rises a tube, H, which communicates with the interior of the glass tubes E E by channels f in the traverse G, and into which is placed the lower or negative carbon, F'.

On the top of the tube H is firmly secured a cap, I, which forms the guide for the lower carbon, F', and from the upper end of which branch detaining-tin gers g, by preference made of refractory material. These fingers are so shaped that they bear against the sides of the tapering end of the lower carbon, F', and by this means the carbon is prevented from being forced up beyond the desired point by its impelling de- E E the holder H is supplied with a liquidsuch as mercury-in such a manner that it has a tendency to force the carbon F' upward, and hence the carbon moves upward automatically as it is consumed, and its point maintains the required position without manual interference. When the carbons F F' have been properly adjusted, and before a current of electricity is passed through the 1amp,the rod B sinks down until the pointof the carbon F meets that of the carbon F'. y

InthecavityofthehelixAisinclosedaspring, la, which surrounds the rod B and is connected at one end to the upper end of the core C, and at its opposite end to the cap closing the cavity in the helix, thus constituting asupport for both the core and the rod. The tension of this spring k is so adjusted that it counterbalances the weight of the core C and rod B when the two carbons are in contact, and by its means the core is rendered susceptible to slight variations in the electric current.

It is obvious that a weight can be substituted for the sprin g k.

source of electricity being attached to the traverse G, while the other pole is connected vice, next described. Through the glass tubes IOO Now, one pole of a battery or other suitable I through the helix to the traverse A', the electric current passes from the latter through the helix A, rod B, and carbons F F down to the traverse G, thus completing the circuit. The core C, by the force of the axial magnetism thus created, is drawn up within the cavity of the helix, carrying up with it the rod B and carbon F, and as the carbons are thus separated the electric lightis produced. Byaproper adjustment of the tension of the spring 7c or its substitute the carbon F is raised by the core C exactly to the desired distance from the carbon F', provided the strength of the electric current remains uniform; but in order to prevent the rod B from rising up too far, the stop e is applied to it, and so adjusted that the carbon F can be raised only a little beyond the desired distance. As the carbons burn away the carbon F sinks down by its inherent gravity, and the carbonF' is raised by the action ofthe liquid in the holder H, and hence aconstant voltaic arc is maintained at one and the same point or focus; but if, from some cause-such, for instance, as the formation of a crater on the negative carbon, which is liable to break 0E- the voltaic arc should be increased, thereby diminishin gthe strength of the electric curren t, owing to the increased resistance, then the magnetism of the helix is weakened, and accordingly the core. The rod B and the carbon F move downward, by force of gravity, until the consequent shortening ot the voltaic arc increases the strength of the current and stops the downward movement; or if, from any cause, the voltaic arc should be increased, and consequently the force ofthe electric current weakened, to such an extent that the core C, rod B, and carbon F are permitted to sink down until the point ofthe carbon F comes in contact with the point of carbon F', then the strength of the current increases instantly to such an extent that the core and rod B are raised until caught up by the stop e, and the correct voltaic arc is immediately restored. If the carbonF has been consumed, the lower tubular section, B', ofthe rod B is unscrewed, and after a fresh carbon has been introduced, said section is replaced. Ifthe carbon F' is consumed, the cap I is taken off, so that a fresh carbon can be introduced into the holder H.

An additional advantage of the glass tubes E E, connecting the traverses A' G, is that they produce much less shade than the metal lic rods or standards usually employed in elec` tric lamps.

I am aware that the detaining-tingers have been applied to a carbon-holder which is connected to the armature ofan electro-magnet by clamping devices, the carbon being forced downward by means of a weight arranged in the holder, and also that the axial magnetic core has been used in combination with a rod sliding through it, and suoli not being within the scope of my invention, I hereby disclaim the same.

What I claim as new, and desire to secure by Letters Patent, is-

l. In an electric lamp,the combination, with the helix A and its axial magnetic core C, ofa rod, B, which is fixed to the core and slides freely in the helix together therewith, a carbon placed loosely into the lower hollow end, B', ofthe rod B, and detaining-tingers arranged on the lower end of said rod to act upon the conical end ofthe gravitating carbon1 all constructed to operate substantially as described, for the purpose set forth.

2. In an electric lamp,the combination, with the helix and its loose axial magnetic core C,of a rod, B, which is fixed to the core and slides freely in the helix together therewith, a carbon placed loosely into the lower hollow end, B', of the rod B,detaining fingers arranged on the lower end of said rod to act upon the conical end of the gravitating carbon, and a stop, e, secured to the rod B, all constructed to operate substantially as described, for the purpose set forth.

3. In an electric lamp, the combination, with the helix A and its loose axial magnetic core C, of a rod, B, which is fixed to the core and slides freely in the helix together therewith, a carbon placed loosely into the lower hollow end, B', of the rod B, detaining-tingers arranged on the lower end of the rod to act upon the conical end of the gravitating carbon, and a balance spring or weight supporting the core and rod, all constructed to operate substan tially as described, for the purpose set forth.

4.. In an electric lamp, the combination, with the helix A and its loose axial magnetic core C, of a rod, B, which, is fixed to the core and slides freely in the helix together therewith, a carbon placed loosely into the lower hollow end, B', of therod B, detaining-fn gers arranged on the lower end of the rod to act -upon the conical end of the gravitating carbon, a stop, e, fastened to the rod B, and a balance spring or weight supporting the core and rod, all constructed to operate substantially as described, for the purpose set forth.

5. The combination, in an electric lamp, of a holder, H, for the lower carbon, constructed to receive a liquid, such as mercury, whereby the carbon is automatically forced upward, and detaining-ingers arranged on the upper end of the holder to act on the conical end of the carbon, substantially as described,for the purpose set forth.

6, The combination, in an electric lamp, of two carbons, F F', a holder, B B', in which the upper gravitatin g carbon, F, is free to move, detaining-flngers, which are attached to the holder B B' and allow the carbon F to sink down by its inherent gravity as its point is consumed, a holder, H, for the second or lower carbon, F', constructed toIreceive a liquid, such as mercury, whereby the lower carbon is autoA matically forced upward, and detainin g-fin gers arranged on the upper end of the holder H to bear against the conical end of the lower carbon, all constructed to operate substantially as described, for the purpose set forth.

7. In an electric lamp, the combination, with IOS IIO

the helix A and its loose axial magnetic core C, of a holder, B B', xed to the core and sliding together therewith in the helix A, a carbon placed looselyinto said holder, detainingfingers b, arranged on the lower end of the holder B B' to act on the conical end of the gravitating carbon, a holder, H, for the second or lower carbon, F', constructed to receive a liquid, such as mercury, whereby the lower carbon is automatically forced upward, and detaining-flngers arranged on the upper end of the holder H to act on the conical end of the lower carbon, all constructed to operate substantially as described, for the purpose set forth.

S. In an electric lamp, the combination, with the helix A and :its loose axial magnetic core U, of a holder, B B', fixed to thc core C and sliding together therewith in the helix A, a stop, e, secured to said holder, a carbon, F, placed loosely in the holder, detaining-ngers b, arranged on the lower end ofthe holder to act on the conical end of the gravitating-carbon, a holder, H, for the second or lower carbon, F', constructed to receive a liquid, such as mercury, whereby the lower carbon is automatically forced upward, and detaining-tingers arranged on the upper end of the holder H to bear against the conical end of the lower carbon, all constructed to operate substantially 3o as described, for the purpose set forth.

9. In an electric lamp, the combination, with the traverse A' and the holder B B', for the upper carbon, F, of glass tubes E E, a traverse, G, and suitable channels leading from the glass tubes into the holder H, substantially as described, for the purpose set forth.

In testimony whereof I have hereunto set my hand and seal in the presence of two subscribing witnesses.

' LEO' DAFT.

[L. s] Witnesses:

W. HAUFF,

E. F. KASTENHUBER. 

